There exists a wide variety of food products that require to be coated with a substance (e.g. powder, liquid, suspension, etc) during their preparation. For example, snack foods such as potato crisps and corn chips are usually coated with a flavouring agent. It is generally desirable to be able to achieve a uniform and controllable coating over the entire surface of a product. Chewing gum is another product that can have powdered non-stick agents and optionally flavouring applied. Equally, bakery products such as pizzas, rolls and buns are dusted with flour to prevent adjacent products sticking to each other or sticking to packaging.
Chewing gum, commercially distributed as pieces such as sticks, which may be coated, is typically produced by combining chewing gum components including a gum base, flavours, sweeteners, fillers, and binders; extruding such combined components into a slab of typically tacky gum composition material; rolling such slab into a uniform flat sheet of a desired thickness and width; scoring the uniform flat sheet into individual pieces; and ultimately packaging the resulting pieces. During processing, the extruded slab of chewing gum material must pass through a series of rollers to produce the ultimate product. In a conventional process, a rolling compound or powdered non-stick agent may be applied to the sheet during processing to avoid sticking or fouling of the rollers by a tacky gum material.
In a bakery factory where pizza bases, buns, rolls and baps etc. are mass produced then individual pieces of rolls, are packaged in a uniform fashion so that packaged buns are of a uniform height—this is especially true of buns for use with burgers. Thus, once the buns have been baked, cooled, compressed by rollers or otherwise and dusted with flour so that they have a significantly reduced tendency to stick to one another and to any packaging. In order to prevent sticking of product with respect to process machinery and or packaging, an excess of a rolling compound or powdered non-stick agent will typically be applied.
Present systems for the application of dusting/coating/flavouring rely upon several methods, two of which shall be discussed briefly. In the case of generally glutinous products such as confectionary and gum, upon extrusion of a cylindrical glutinous product is fed into a powder vat, fed through a roller to increase a width and reduce a thickness of the material, fed into and through further sets of powder vats and rollers. This will commonly be happening at speeds of 1-5 ms−1. In the case of a bakery, scarf feeders or dusting curtains will continuously apply flour—possibly flavoured or additionally/alternatively of a sweet powder. With reference to FIG. 1, there is shown—from U.S. Pat. No. 2,604,056—where, in a candy-gum manufacturing process, an open bottom feed chute 17, 18 is arranged in close proximity to a roller surface 14 or conveyor surface 9. It is notable that this system shows a dust receiver tray, indicative that heavy powders are lost—whilst fine powders will inevitably enter the atmosphere to form an aerosol atmosphere.
In each of such systems the issue is that the powder used in a manufacturing processing stage is effectively applied indiscriminately. Powder applied to rollers and conveyor belts will fall off, with only a small proportion ending upon the desired product. The powder application material is dispersed and a significant amount is wasted. In a confectionary factory, the powder will find its way between rollers and conveyors and ingress between seals in machinery. The atmosphere of the factory will be saturated with particles and becomes an aerosol environment; personnel will need to wear masks; air conditioning ducts and filters need to be cleaned frequently; the fine particles of the aerosol will settle and plant and machinery need to be cleaned frequently. Importantly, there is significant waste of powder product. Additionally the service intervals for the plant are reduced in time because of the additional load on the machinery (bearing seal ingress, for example) and the need to clean control machinery, which will typically have cooling air systems, having filters that also need to be cleaned or replaced.
In view of the above, the use of extensive amounts of a rolling compound or powdered non-stick agent typically causes manufacturing difficulties in controlling powdered material in the atmosphere, adds to manufacturing cost, creates difficulties in handling, increases processing time, may increase volatization of flavours and may apply desired product in a porous non-uniform outer surface.